Organic/Silicon 3-terminal Tandem Solar Cells – ORGANIST

The ORGANIc Silicon Tandem (ORGANIST) develops a new concept of hybrid Organic/Silicon tandem solar cells. This project is particularly innovative and is built on recent progress in PV research:
(i) the recent discovery of non-fullerene semiconductors has given rise to a spectacular growth of organic PV (OPV) performances in recent years: the best single junction polymer solar cell is reported at 19%. Moreover, a recent report estimated OPV stability over 30 years, making OPV a credible solar technology to be combined with c-Si in tandem configurations.
(ii) The 3-terminal (3T) tandem cell design based on an interdigitated back contact (IBC) silicon cell with a thin conductive connection to a wider bandgap top cell. This design is not limited by the current matching constraint of a 2-terminal (2T) tandem cell and avoids the need for a technologically challenging tunnel junction. It also offers the flexibility of a 4-terminal (4T) tandem cell without the grid alignment constraint.
Organic materials offer a large choice of bandgaps (>1.6eV) and very good absorption at high energies, making their association with a silicon bottom cell very promising. The aim of the project is thus to develop 3T Organic/Si tandem solar cells. The technical potential is important and is supported by a strong industrial and societal potential due to the combination of industry-standard Si technology and low cost printed OPV technologies.